java線程池參數動態化方案

前言：jdk提供了一套下線程池參數動態化的api，阻塞隊列的長度考慮lilnked擴容機制
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ThreadPoolChangeDemo {

    public static void main(String[] args) throws InterruptedException {
        dynamicThreadPool();
    }

    public static ThreadPoolExecutor buildThreadPool(){
        return new ThreadPoolExecutor(2,
                50,
                60,
                TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(50),
                new ThreadFactory() {
                    @Override
                    public Thread newThread(Runnable r) {
                        return new Thread();
                    }
                });
    }

    private static void dynamicThreadPool() throws InterruptedException {
        ThreadPoolExecutor threadPoolExecutor = buildThreadPool();
        for (int i = 0; i < 15; i++) {
            threadPoolExecutor.submit(()->{
                printPoolSize(threadPoolExecutor,"創建線程池！！！！");
                try {
                    TimeUnit.SECONDS.sleep(5000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            });
        }
        printPoolSize(threadPoolExecutor,"改變之前");
        TimeUnit.SECONDS.sleep(1);
        threadPoolExecutor.setMaximumPoolSize(100);
        threadPoolExecutor.setCorePoolSize(50);
        threadPoolExecutor.prestartAllCoreThreads();
//        Resize linkedBlockingQueue = (LinkedBlockingQueue) threadPoolExecutor.getQueue();
        printPoolSize(threadPoolExecutor,"改變之後");
    }

    private static void printPoolSize(ThreadPoolExecutor pool,String name){
        LinkedBlockingQueue linkedBlockingQueue = (LinkedBlockingQueue) pool.getQueue();
        System.out.println(name);
         System.out.println("最大線程數:"+pool.getMaximumPoolSize());
        System.out.println("核心線程數:"+pool.getCorePoolSize());
        System.out.println("線程池活躍度："+(pool.getActiveCount()/pool.getMaximumPoolSize()));
        System.out.println("隊列大小："+linkedBlockingQueue.size());
        System.out.println("隊列剩餘大小："+linkedBlockingQueue.remainingCapacity());


    }
}